January 8, 2016
Atlas Copco Rental Oil-Free air compressors created an underwater buffer during the implosion of a San Francisco pier. The San Francisco Bay being a significant ecological habitat in California, words like explosives and implosion generated concern when they were used to discuss how the 80-year-old San Francisco–Oakland Bay Bridge’s 21 piers should be demolished.
But when the implosion was conducted in November 2015, the problem was solved using an innovative curtain bubble strategy - a method that places curtain of air bubbles around the site in order to protect marine life.
The feat was successfully completed on Pier E3, the largest of the piers—the equivalent of a five story concrete building. General contractor Kiewit/Manson was in charge of the operation, using Atlas Copco Rental 1,600 cfm oil-free compressors to supply air at full capacity to the blast-buffering bubble curtain. Blake Gearhart, Vice President of Operations West for Atlas Copco Rental North America, pointed out that the air compressors are California Air Resource Board (CARB) permitted.
“ Kiewit/Manson is a socially responsible company and they needed diesel-powered air compressors. We were an obvious choice because our compressors are CARB permitted,” Blake Gearhart said. ”
Atlas Copco compressors were used at implosion of San Francisco pier to protect marine life.
Brian Ford, Atlas Copco Rental Area Sales Manager out of Livermore, Calif., said assembling a fleet of so many 1,600 cfm compressors for a job is not a small undertaking. “We were confident we could provide what they needed,” Ford said. “We have the largest fleet of 100% oil-free air compressors that are both diesel powered and CARB-permitted in North America.”
Ford said the high-volume Atlas Copco Rental models were particularly well suited to an environmentally sensitive project because they introduce 100 percent oil-free air into the water.
As an added measure of safety, each compressor’s base provides fluid containment.
The demonstration was streamed live online and given live coverage on television. The compressors maintained the curtain without problem.
“This pier implosion was the culmination of years of collaborative preparation and planning,” Leah Robinson-Leach, Bay Bridge spokesperson from the California Department of Transportation. “The combination of science, technology and engineering with environmental stewardship is historical.”
For six seconds, a sequential series of blasts from 600 explosive charges rumbled through the structure, fracturing the reinforced concrete, which collapsed into the pier’s own honeycomb-like base below the bay floor. It left nothing to retrieve but the blast covers floating in the foam, which had been placed over the structure to protect against potentially flying rock.
CalTrans reported: “Initial studies including three days of round-the-clock observation after the blast have determined no injuries or deaths to aquatic wildlife.”
“ This method has proven itself to be the most cost-effective and environmentally friendly," said Bay Bridge chief engineer Brian Maroney. ”
The successful demonstration of blasting in the bay may now be used on the other piers, all that remains of the Bay Bridge after construction of a new Skyway between San Francisco and Oakland.
Written by Olivia Gambin